1. Field of the Invention
The present invention relates to a method of manufacturing hollow molded articles, such as chocolates, candies, dolls, stationary ornaments, and the like, using an elastic molding die.
2. Description of the Prior Art
Hollow molded articles, such as hollow chocolates, hollow candies, dolls, stationary ornaments, and the like, are conventionally known. Such hollow molded articles are manufactured using a plurality of separable molding dies made of a rigid material with a shape conforming to the shape of the articles to be molded. The materials to be molded of an amount smaller than the internal volume of the separable molding dies are fed into the molding dies through their opening ports, and, after closing the opening ports, the separable molding dies are installed in a spinner to be rotated in all directions. The materials to be molded are solidified along the internal surface of the separable molding dies to form hollow articles, while the molding dies are rotated in all directions. After this, the separable molding dies are divided to take out the hollow molded articles.
The hollow molded articles manufactured by this type of separable molding dies, however, have partition lines of the separable molding dies on their surface, giving rise to the deterioration of their commercial value. In particular, a number of separable molding dies are required when complicated hollow molded articles are to be manufactured, making it difficult to manufacture hollow molded articles with a beautiful surface appearance. The use of many separable molding dies also renders the manufacturing process complicated. In addition, because the separable molding dies are made of rigid materials, their manufacturing cost is significant, greatly affecting the manufacturing cost of the hollow molded articles. In particular, in the case where a variety of different hollow molded articles are manufactured, each in a small number, a significant portion among the total manufacturing cost of the hollow molded articles must be shared by the cost for manufacturing the separable molding dies. It is thus extremely difficult in actual practice to manufacture such hollow molded articles at an acceptable cost. Furthermore, conventional separable molding dies made of synthetic resin such as polycarbonate exhibit poor heat conductivity, giving rise to an impaired work efficiency in the molding operation for manufacturing hollow molded articles, for which heating or cooling are essential in order to solidify the material to be molded while the separable molding dies are rotated in all directions.